A133758 Total number of restricted left truncatable primes in base n.

0, 3, 5, 4, 149, 7, 144, 37, 1442

Offset

2,2

Comments

Prime digits p in base n are counted if there is no prime with 2 digits which can have its leftmost digit removed to produce p; e.g., in base 10 the prime digits 2 and 5 are counted, because there are no primes containing them as rightmost digit.

References

Steven Kahan; Sol Weintraub: Left truncatable primes. In: Journal of recreational mathematics 29 (1998), pp. 254-264.

Links

Table of n, a(n) for n=2..10.

I. O. Angell and H. J. Godwin, On Truncatable Primes, Math. Comput. 31, 265-267, 1977.

Eric Weisstein's World of Mathematics, Truncatable Prime

Chai Wah Wu, On a conjecture regarding primality of numbers constructed from prepending and appending identical digits, arXiv:1503.08883 [math.NT], 2015.

Index entries for sequences related to truncatable primes

Crossrefs

Cf. A076623, A055521.

Sequence in context: A161353 A360449 A182045 * A350904 A242288 A021742

Adjacent sequences: A133755 A133756 A133757 * A133759 A133760 A133761

Keyword

nonn

Author

Martin Renner, Jan 04 2008

Status

approved